This is what I've been using for all of my batches because my water is extremely hard. What I've been wondering is whether this water is stripped of nutrients completely or what. I guess I really dont understand the exact ph or analysis of RO water. I'd like to tailor my water to the beer. However, I'm not sure on the exact specifics of what I'm dealing with.

RO water has no salts at all and my guess is that they neutralize it a fair amount. Most bottled water is somewhere between 6.2 and 7.9 I think so it isnt truelly neutral but it is close. So you went from extremely hard water to completely soft water. Where do you get RO water. Is it just bottled.

I am in the same situation as you. Over 99% of everything is removed from reverse osmosis water therefor it naturally has a low pH of around 5. It makes a nice base if you want to build your water up to the style. I usually just add a teaspoon or so of burton water salts per 5 gallons, or more or less if the style specifically calls for a certain level of hard/softness in the water. I use the 5 star pH stabilizer but I think on my next batch I will try it without and test the pH to see if it is necessary.

I use distilled water for mashing and I've gotten efficiency between 84-91% with every batch.

Using distilled water also gives me a softer hop edge in my beer, which I enjoy and consider an advantage.

RO water, like distilled water, is stripped of practically everything (... but it's only "pure" until you add something to it like, say, 10 lbs of malted barley). You can consider it to have no ions ("salts") of interest for all practical brewing purposes.

I use distilled water for mashing and I've gotten efficiency between 84-91% with every batch.

If i remember correctly, though, mashing efficiency is completely separate from yeast health. You can get a decent extraction, but your yeast's health could suffer in the long-run given a deficiency of the proper ions.

That's how i understand it, and why i'll never use 100% RO/DI water for the full water load in a batch.

If i remember correctly, though, mashing efficiency is completely separate from yeast health. You can get a decent extraction, but your yeast's health could suffer in the long-run given a deficiency of the proper ions.

That's how i understand it, and why i'll never use 100% RO/DI water for the full water load in a batch.

My percent attenuation has been within the range that White Labs specifies, too. I don't have a microscope to examine their condition, but regardless they're getting the job done and seem to do a great job turning the wort I give them into tasty beer.

I don't re-use yeast from batch to batch, so I'm not really worried about the long-term health of my yeast per se.

Distilled and RO water both strip any kind of mineral content out of the water. Some of which are very beneficicial to making good beer. If you have extremely hard water perhaps using a mixture of distilled/RO water with some tap water in it would be the way to go.